Almost all companies have complex legacy application environments. Such an environment consists of all the applications, programs, and data that a company depends on to successfully manage its day to day operations. Within these applications, programs, and data are encapsulated one or more meta-models of the company's physical, intellectual, and financial assets.
An enterprise meta-model of a complex legacy application environment defines the ontology for these assets, and the enterprise meta-model can evolve and change over time. Beyond changes to the enterprise meta-model, the instance data that is referenced through the enterprise meta-model will also very likely change over time.